Tuning instability and intonation are different
If an open string starts in tune but changes after a bend or tremolo use, you are describing tuning instability. If the open string stays correct but fretted notes sound wrong, intonation or another playing adjustment may be involved. Tell the workshop which pattern you hear.
Use a tuner and repeat one simple test at a time. Tune an open string, play normally, then check it again. Separately compare how a familiar chord sounds. A description such as “the G string drops after bends” is more useful than “nothing stays in tune.”
Start with strings and recent changes
Old strings and a change of string gauge are useful clues. Mention when the strings were installed and whether the problem started immediately afterwards. Also mention a different tuning or a change in tremolo setup.
Look for obvious installation problems or damage without pulling parts apart. If you do not know how the bridge or locking system is meant to work, bring that question to the technician rather than changing several settings to see what happens.
Do not buy new tuners before checking the cause
Tuning machines are only one part of the string path. A technician may also need to examine the nut, bridge contact points, string installation and moving hardware. Replacing a functioning tuner will not correct a problem elsewhere.
A pinging sound at the nut or a change after tremolo movement is worth reporting. Those clues guide the inspection; they are not confirmation that a particular replacement part is necessary. See custom nut work and tuning-machine installation for the separate services.
When chords sound wrong despite a correct tuner reading
Fretting stretches a string, and the way the instrument is adjusted affects the resulting note. String condition, action and other factors can matter. A tuner reading for an open string does not establish that the whole fingerboard is playing as intended.
A setup can include intonation adjustment where the instrument’s design allows it. Acoustic and electric bridges offer different adjustment options, so avoid assuming an acoustic saddle can be moved like an electric one. Explain which chords and fret positions bother you.
What to include in a tuning repair enquiry
List the affected strings, your tuning, string gauge if known, and the action that causes the change. Mention a floating bridge, locking nut, recent hardware installation or previous repairs. A short before-and-after tuner clip can help show an intermittent problem.
Favaran offers setup assessments near Davisville & Yonge and arranged pickup/drop-off across the GTA. Request an estimate before purchasing parts so you can choose work that addresses the actual cause.